Unfortunately, lovebirds are diamorphic which means that just by looking at them you will not be able to tell their gender. So you have to DNA test them ... I sent in one of my birdie's feathers to an avian lab that tests. I think it cost me around $35.00. Here's the link, in case you or anyone else is interested: [link]

You can go to that website and they will let you mail them your sample! The actual lab is about 2,000 miles from where I live. But I have some friends who have lovebirds who do not care to know the actual sex of their birds. They aren't breeding them, so they don't really care to know. I wanted to know simply because I felt weird NOT knowing! lol